I-123 radioiodinated 3-fluoropropyl-nor-β-CIT (i.e., compound I) is a diagnostic agent useful for diagnosing and monitoring movement disorders and dementia, and has specific use in the diagnosis and monitoring of Parkinson's disease. I-123 radioiodinated 3-fluoropropyl-nor-β-CIT has the following structure:

This compound can be prepared from anhydroecgonine methyl ester using a six step process, which relies on the conversion of an arylstannane precursor to the I-123 labeled compound. Such a process is generally disclosed in, for example, Swahn, et al., Journal of Labelled Compounds and Radiopharmaceuticals, 1996, Vol. XXXVIII, No. 7, p. 675-685. See also U.S. Pat. No. 6,447,747 (disclosing halogendestannylation reactions). The reaction scheme commonly used to prepare I-123 radioiodinated 3-fluoropropyl-nor-β-CIT is set forth below:

The preparation of the arylstannane precursor requires the use of the highly toxic tin reagent hexamethylditin. The safe use of hexamethylditin requires engineering controls and substantial personal protective equipment. There is thus a need for a process for the production of I-123 radioiodinated 3-fluoropropyl-nor-β-CIT that does not require the use of hexamethylditin.
Additionally, previously known methods for the conversion of a nortropane to the corresponding N-(3-fluoropropyl) analogue relied on alkylations using 3-fluoro-1-bromopropane. See, e.g., Swahn, et al., Journal of Labelled Compounds and Radiopharmaceuticals, 1996, Vol. XXXVIII, No. 7, p. 675-685. However, 3-fluoro-1-bromopropane is known to be an ozone depleting compound. There is thus a need for a process for the production of N-(3-fluoropropyl) analogs of nortropanes, and in particular I-123 radioiodinated 3-fluoropropyl-nor-β-CIT, that does not require the use of 3-fluoro-1-bromopropane.